Volkswagen combines sport with efficiency in Polo Blue GT

At the 2012 Geneva Motor Show, Volkswagen introduced a performance model whose primary claim to fame is its efficiency. The Polo Blue GT has dimensions close to those of the original Golf GTI, but thanks to a 140-hp (104-kW) turbocharged, direct-injected 1.4-L I4 engine with automatic stop/start, cylinder deactivation, and a seven-speed dual-clutch transmission, it achieves a rating of 50 mpg in the combined city/highway European driving cycle.

Such efficiency might imply a lack of performance, but the Polo Blue GT accelerates to 62 mph (100 km/h) in just 7.9 s and reaches a top speed of 131 mph (211).

The new engine is the top configuration in the company’s new EA211 family of gasoline engines and has cylinder deactivation. Running on two cylinders could be troublesome for NVH purposes, but at the car’s introduction, Ulrich Hackenberg, VW board member responsible for technology, insists that the cylinder deactivation is seamless.

Drivers may not notice, but VW promises the gas gauge will. Shutting off two cylinders during light- and medium-load conditions gives an 8-mpg boost to the European rating. At constant speeds, the benefit is ever greater; 16 mpg at a steady 31 mph (50 km/h) and 11 mpg at 43 mph (69 km/h).

The cylinders deactivate between 1250 and 4000 rpm, a range when the engine makes between 18 and 74 lb·ft (24 and 100 N·m). This covers nearly 70% of the European driving cycle.

The switch between two and four cylinders occurs within have a camshaft revolution—between 13 and 36 ms, with the transition smoothed by appropriate adjustments to ignition timing and throttle position.

During the cut-and-thrust of urban driving or when thrashing the GT on country roads, the engine management system recognizes the driver’s intent and doesn’t engage the cylinder deactivation.

All EA211 engines feature a variable intake cam with 50 degrees of adjustment to support fuel efficiency, low emissions, and strong low-end torque. The Polo Blue GT adds a variable exhaust cam phaser, too, reinforcing torque at both high and low revs.

The car goes on sale in Europe in July, but there are no plans to import it or any other current-generation Polo subcompact or Up! minicar to the U.S., said Jonathan Browning, President and CEO of Volkswagen Group of America. In the current market, there is still insufficient demand for such small cars, he said.

“Over time, [whether future generations are imported] depends on gas prices,” he said.

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